package 简单.平衡二叉树;

public class Solution1 {
    public boolean isBalanced(TreeNode root) {
        return recur(root) != -1;
    }
    public int recur(TreeNode root){
        if(root == null) return 1;
        int left = recur(root.left);
        if(left == -1) return -1;
        int right = recur(root.right);
        if(right == -1) return -1;
        return  Math.abs(left -right) < 2? Math.max(left,right)+1 : -1;


    }
}
